Why do we use normal saline to dilute serum instead of distilled water ?

Answer 1

<<Normal saline is an isotonic solution, meaning that it has the same salt concentration as the body. If you used sterile water for the purpose of serum dilution, the cells would swell and burst because water would be drawn into them. If you used a hypertonic solution (greater content of salt than in the body), the cells would shrivel up because the water would be drawn out of them. Isotonic solutions are the same as the body, so the cells can maintain their normal appearance. Kind of like the story of Goldilocks and the three bears. Hypertonic solutions are too salty. Hypotonic solutions (such as water) are not salty enough. And isotonic solutions (normal saline) are just right! :>>